Fifteen Minutes
by TheBigCat
Summary: Solving a murder mystery on a train? All in a day's work for the Doctor and Ace.
1. Murder Is Easy

**Chapter One**

**Murder Is Easy**

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><p>The rain was pouring down in buckets outside of the small, out-of-the way train station as businessmen and tourists hurried past, heads bowed and occasionally looking at their mobile phones. In the twenty-first century, there wasn't much anyone seemed to want to do except text. Everyone was so occupied in their own little social worlds that seemed so important to them that no one at all noticed the peculiar sound that was coming from around a corner. A sound that was almost exactly the sound you'd expect to hear if the fabric of time and space was pushed carelessly to the side by a 1960s police box and closed neatly behind it. But nobody turned to stare, no-one clicked a picture on their phone and sent it careening throughout the vast tunnels of the internet and turned it into a viral phenomenon. Which, coincidently, was just how the owner of the box liked it.<p>

The door creaked open, almost hesitantly, and an ordinary-looking girl in a light blue dress and black jacket stepped out. She looked back and forth, examining the place, before her eyes came to rest on a large sign announcing where they were.

"All clear, Professor!" she called cheerily into the blue police box. "The train station, just like you said. Which makes a change."

"_Ace._" A small man with a brown overcoat and a funny little hat perched on top of his head stepped out to join her. He looked up at the sky, and the overcast clouds, and finally at the wetness all around them. "Oh, dear. It does seem to be raining quite a bit, doesn't it?"

"Yeah, and I'm getting drenched," his companion said, pulling her jacket tightly around herself, as if to ward off the rain. "Would you mind actually putting that brolly of yours to work?"

"Respect the umbrella," he scolded, but pulled his red-handled umbrella from his side and opened it with a masterful flick of his wrist. He held out his arm to his friend, and she linked hers neatly through it. They walked side-by-side into the station, chatting and grinning together.

"What do you know about train stations, Ace?" the Doctor asked. She wrinkled her nose a bit.

"Not a lot. I didn't exactly pay attention in school, did I?"

He shook his head a bit, and then began to lecture her about the full history of underground subways and railway lines in full. She was only half-listening to him, and let her mind wander a bit, glancing around. There was a mother with several children, looking more than slightly harassed as they all tried to pull her in different directions at once. A _lot _of people texting. A young couple, not much older than her, sitting across a table, writing to each other on phones.

Wait.

What was that? Voices, raised. "_Dammit, let me go!_"

The Doctor, next to her, kept chattering on, oblivious. She held up a hand to stop him.

"Professor, can you hear that?"

He stopped. "Hear what?"

She listened anxiously, glancing back and forth. "It sounded like two people arguing. And... somebody hit something."

The speakers above them crackled into life. "_Train Line Two, arriving._"

The Doctor smiled at her. "It was probably just your imagination."

"Yeah, probably." She relaxed a bit. She couldn't hear anything, now. Her eyes flicked across the station again, and saw someone. The figure was indistinct, but he was quite clearly pushing a woman sharply in the chest. _Onto the tracks._

And then, an ear-deafening _screech _as a train pulled into a station, and another scream, more human. Before she knew it, she was running, dragging the Doctor along with her. She stopped at the side of the tracks. "Oh, no," she whispered. The side of the train was splattered with blood. And down, next to the train...

"Poor girl."

"Suicide, do you think-"

"-should call her family-"

"-who's going to get the body?"

A crumpled, broken figure, on the ground. She was blonde and petite, and had a pink Hello Kitty satchel slung over her shoulder. A brown leather cord lay inexplicably over her body, and shards of glass (maybe from a broken window?) glinted around her. Ace absorbed this all with an almost detached interest. Someone had died, and there was no way that they could have stopped it. They hadn't even _expected _it to happen. It was meant to be a break from saving the world.

You don't often get a holiday with the Doctor, though. She knew that perfectly well.

"Ace." Someone was tugging at her sleeve. She looked over. It was the Doctor. "Ace, come away. Please."

She allowed herself to be led over to a bench, and the Doctor sat down next to her. "Are you all right?"

Reality snapped back to her with a _twang _like a rubber band, and she blinked. "Yeah. Yeah, I'm good. It was just..."

"Unexpected?" he offered quietly. She suddenly realised that he probably thought she was in some state of shock. And on some level, she probably was. But she couldn't afford to think like that right now. A girl had _died. _She had to do something. No, _they _had to do something.

"I'm fine," she said, nodding firmly. "Doctor, that girl didn't commit suicide. She was _pushed. _I saw her."

He looked at her entirely seriously. "Did you see who pushed her?"

And that was the amazing thing about the Doctor. He believed her, even when she half didn't believe herself. He had a remarkable ability to make anyone at all seem incredibly important, no matter how lowly they seemed.

"He had a beige coat," she said hesitantly. "And... I _think _he pushed her with his right hand."

"Good." He jumped up, and strode over to the rapidly growing group of people gathered around the side of the track where the girl's body lay. Ace, after a moment, followed him. They stood together at the edge of the platform, looking down. "What do you think?"

She thought for a moment. "Whoever did it wouldn't want to stick around. He would have hopped the next train out of here."

"My thoughts exactly," he said, tapping her on the nose. "And there's only one train going out of this station right now."

She looked over, to the other side of the station. The logical- no, the _only _place the murderer could have ran to was that compartment of that train just over... there. The train in question was meant to be leaving at half past eleven. She looked up at the clock. _11.34._

"Professor, the train's leaving!" she exclaimed in horror. He was already dashing across the station, clutching his hat to his head, and yelling at her to follow him.

"_Doors closing."_

He leapt inside the compartment, jammed the door open with his brolly, pulled Ace easily inside, and plucked the makeshift holder from the gap. Ace gasped for breath, and looked around. Apart from them, there were six passengers in the compartment. Three women, three men. A nice even split, which left them with three possible murderers.

On a train compartment, with someone who had just murdered a girl- pushed her onto the tracks, no less. Ace could think of better ways to spend a break from saving the world.

And the worst bit was that the train was arriving at the station in 15 minutes exactly. If they didn't catch the person by then, he'd escape. Possibly to kill someone else.

* * *

><p><strong>To be continued...<strong>


	2. Secret Adversary

**Chapter Two**

**Secret Adversary**

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><p>The Doctor sat down a bit away from everyone else, and Ace took the seat beside him. He pulled a newspaper casually out from his pocket and pretended to read while he thought. At least, that was what Ace hoped he was doing. It would be pretty irresponsible of him to sit there reading the news while a killer was on the train with them. Ace pictured him doing that for a moment, just to amuse herself. <em>Ace, would you mind not bleeding to death all over the comics? I wanted to read the sports section.<em>

She almost laughed, and then caught herself.

Having no reading material to distract herself with, she took to examining the passengers, and nearly swore out loud. All three of them had beige coats. The tall one with black hair, the one holding onto one of the handles running above the seats, had a light brown-ish coat (that could be easily seen as beige) looped over his left arm. A pair of reading glasses were sticking out of his back pocket. The second man had his tan jacket tied around his waist, and his hair was soaked through. He had a mobile phone in his other hand and was reading the screen with obvious interest. The last bloke had his left arm in a sling, and his coat was lying in a sopping wet puddle on the ground next to him. It appeared to have been soaking wet from the rain.

"You said that the girl was pushed with his right hand," the Doctor said under his breath, still looking at the newspaper. It took a second for Ace to register he was talking to her.

"I think so," she said. "I'm not certain."

He lowered the paper ever so slightly, and winked at her. "I trust your observational abilities. So, three possible people?"

Suddenly, Ace wasn't sure any more. "Couldn't they have just walked out of the station?"

He shook his head. "I don't think so. The victim was standing at a news stand. There weren't any people on the platform behind it. And I didn't see anyone at the exit. So..."

"So everyone on the platform got on this train," Ace said, completing the thought. "They could be in another compartment, though."

"This whole thing happened near the edge of the platform. They wouldn't have had time."

Ace closed her eyes for a moment, and thought. "Right, then." She opened them, and checked the time. There was 13 minutes until the train pulled into the next stop. Thirteen minutes to find a murderer out of three people. She stood up suddenly. "Listen up, you lot!"

Everyone looked at her, including the Doctor.

"_Be careful, Ace,_" he hissed under his breath.

"I said," she barked firmly. "Listen _up_! That girl back at the station who 'fell off the platform'. She was _murdered. _Do any of you care?"

One of the women sitting down covered her mouth with a hand and gasped a bit. Apart from that, everyone seemed impassive. Maybe they thought she was a loony or something. She forged on anyway. "I saw the exact moment she was killed! And I know that the person who did it was male-" she looked directly at the three men. "-and had a dominant right hand! And, he escaped onto this train." She paused weakly for a moment, and then added, "_do any of you know anything?_" for good measure. No one spoke.

"Ace," said the Doctor, at her elbow. "If anyone had seen it, they would have said something by now."

She blushed scarlet, and sat heavily down. "Damn. I just wrecked it all, didn't I?"

"Yes," he said heavily. "I'm rather afraid you did."

The man holding onto the handle above the seat shrugged. "I'm not a suspect, am I? I'm a left-hander."

The bloke with soaking hair sighed. "I'm right handed. Are you going to arrest me or something because of the way I write?"

They looked at the third person Ace accused, who raised his eyebrows. "Well, I'm left handed as well, but it's not as if I can use it or anything." He raised his sling pointedly. "Any more questions?"

"No," said Ace, slightly abashed. "Sorry."

Everyone returned to what they had been doing previously.

"I'm a right idiot," sighed Ace despondently. "I should have asked you before I did anything."

The Doctor smiled secretively. "_'In every failure lies the seeds of success'_," he quoted cheerily. "Why don't we try the process of deduction, hmm? It's very likely- probable, I might say- that one of these gentlemen is lying."

Ace thought about that for a moment. "So, what you're saying is the person who's lying is the bloke who's just shoved a girl onto the train tracks."

"Quite. Now, I don't think our friend with the broken arm would have been lying-"

"-why not?" interrupted Ace. "He's got a sling, which gives him an easy alibi-"

"-but," the Doctor swiftly cut her off, holding up a remonstrating finger. "It's on his _left arm_. He would have used his right arm whatever the situation."

"Oh," Ace said. She seemed to be messing up rather a lot today. "It could have been a red herring," she said. The Doctor grimaced a bit.

"Duly noted, but that's more the stuffing of a Sherlock Holmes novel than any real life situation."

Ace smiled. "Are you saying that we're Sherlock and Watson?"

He hummed a bit. "If that's so, which of us is which?"

"You'd be Watson, right?" she said. "Because you're the one who's a _Doctor._"

On the other side of the compartment, people were getting slightly restless. "You just accused us of murder," called the man with his arm in a sling. "Aren't you going to follow up on that? Or was it just some high school prank?"

Ace bristled a bit, but the Doctor simply raised his hat in greeting. "Good afternoon. My friend and I were just discussing how it would be impossible that _you'd _be the one to commit murder, sir."

The sling-man looked confused. "Oh. Well- uh, that's all right, then."

"What about us?" The bloke holding onto the roof handle indicated himself and the person with the mobile phone. "Are you saying that one of us did it?"

The Doctor stared coolly back at him. "Yes, I am. Miss Holmes?" He glanced over at Ace. "Would you be so kind to deduce who it was?"

* * *

><p><strong>To be continued...<strong>


	3. Cat Among the Pigeons

**Chapter Three**

**Cat Among The Pigeons**

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><p>Ace froze for a moment. She wasn't good at this type of thing. She usually left the incredible deductive skills and feats of mental acrobatics to the Doctor. As she had put it once, she was the muscle of the operation. She looked over at the Doctor, who gave her the faintest of smiles, and an encouraging nod. She looked at the two remaining men again. The guy with the smart phone.<p>

"You," she said, pointing at him so there could be no mistake. He looked up at her.

"Yeah, what is it?"

"Did you kill that girl?" she asked him bluntly. The reaction was exactly what she had thought would happen. He immediately looked shocked, and said, very loudly, "NO!"

"All right, all right, there's no need to shout," she said, wincing. "Pass me your phone for a minute, would you?"

When he hesitated, she stepped over and tugged it from his hand. Skimming the screen, she could clearly see that he had been texting his girlfriend. She read the first message, and raised an eyebrow. "You might want to go light on the romance, mate. Trust me there."

His ears went red, and she tossed the phone back. "You've been texting on that phone all the time, and you were doing it really well with just one hand- your left one. You're not a right-hander, are you?"

"I told you already," he said, recovering a bit of his bravado. Ace looked to the Doctor for advice, and received a vague nod that told her she was doing the right thing.

Through the process of elimination, they had figured out that two of the three suspects were unlikely to have done the killing. She wasn't ready to strike them off the list completely; being with the Doctor had taught her that, at least. That left one person.

"So," said the Doctor, turning to the man with the overcoat draped over his arm. "What possible motive could you have for murder?

"I told you, I didn't do it," he said, looking annoyed. His facial expressions were convincing, which, in Ace's book, meant absolutely nothing at all. She looked up at the digital clock set above the doors. _Ten minutes. _The landscape rolled serenely past them- buildings, parks, big glass domes holding who-knew-what. She looked at the man.

"No offence," she said sweetly, meaning every offence she could fit into those two words. "But you're the only one here who has no proof of being either right- or left-handed."

He glanced between her and the Doctor. "What about you two, then?"

Ace scowled. "What _about _us?"

"You haven't proven anything, either," he said with the air of somebody who is feeling very, very smug.

Ace opened her mouth to respond, but the Doctor beat her to it once more. "Why would we need to?" he said with a raised eyebrow. "We're the ones telling you about this, after all."

Ace dug in her jacket pockets, pulling out a large sheet of paper. She had taken to carrying around various obscure items just in case they would come in handy during an alien attack or something. She rummaged around a bit more- _signed copy of War and Peace that she hadn't got around to reading yet, prototype sonic hammer that she was building, various alien currencies, a set of ordinary screwdrivers for safe-cracking, slingshot, hanky that was most definitely not hers-_ but couldn't find a pen. "...Professor?" she asked, looking at him.

He produced a new-looking HB pencil from behind her ear, and passed it to her with a slight grin. She took it, and scribbled her name, _Ace McShane, _as well as a quick drawing of a cheetah. All with her left hand. "There you go," she said, handing the pencil back to the Doctor. "Left handed. That enough proof for you?"

He paused, put off for a moment, and then pointed at the Doctor. "What about him?"

"Ambidextrous," the Doctor said proudly, pulled another pencil out, and drew the Seal of Rassilon with his right hand, writing the opening lines from _Moby Dick _with his left. He finished off abruptly, and handed the pencil to the man. "Why don't you prove your innocence, then?"

He hesitated, even took the pencil, and then sighed. "Fine, I lied. I'm right-handed. But I only said it because I didn't want to be accused of anything!"

"Yes, well," the Doctor shrugged. "It's a bit late for that, don't you think?"

"But I'm completely innocent!" he exclaimed. "You won't be able to prove anything, because there's nothing to prove."

The Doctor nodded courteously, and motioned for Ace to sit down again. "We won't bother you again."

As she sat, he whispered to her, "What do you think?"

"I think," she said carefully. "That we've got our man."

He smiled at her. "Good thinking back there."

"Thanks, but that means nothing if we can't prove he's the bloke before we get to the next station."

Together, they looked up at the digital display. _Seven minutes. _How do you root out a killer in seven minutes?

Ace's brain was working hard. What had she seen back at the murder site that could help? She remembered having head something about how the most meaningless details could help solve a crime on some sort of cop show once. She never thought she'd have to ever put that fact into action. Ace closed her eyes, trying the picture the scene exactly as she had seen it.

_A crumpled, broken figure, on the ground. She was blonde and petite, and had a pink Hello Kitty satchel slung over her shoulder. A brown leather cord lay inexplicably over her body, and shards of glass (maybe from a broken window?) glinted around her. _

Her eyes snapped open, and she clicked her fingers together in delight, just because she could, and didn't want to yell something stupid like _Eureka _instead. "Professor," she said, nudging him frantically. "There were shards of glass around the girl's body. I thought they were from a window at the time, but there wasn't a broken window anywhere around."

She could practically see the gears in his complicated Time Lord brain turning underneath the straw Panama hat. He grinned widely, tapped her on the nose, and stood up once more. "Ace," he said. "You are a _genius._"

"Thanks," she said smiling brightly. "Now, let's go and bust this toerag."

* * *

><p><strong>To be continued...<strong>


	4. Towards Zero

**Chapter Four**

**Towards Zero**

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><p>The man with the coat barely glanced up as they approached him again. "You said you wouldn't bother me again," he snapped.<p>

The Doctor tilted his head ever-so-slightly. "We lie occasionally. It's an occupational hazard of our job. We just wanted to ask you... do you happen to wear glasses?"

He frowned. "What kinda stupid question is that? Of course I need glasses. I'm practically blind without them."

Ace bunched her hand into a fist in her jacket pocket. _Gotcha. _"Then why aren't you wearing them?"

He opened his mouth for a moment, and then shut it. "Uh. I dropped them on the station. Look, why are you interrogating me?"

The Doctor put his hands casually in his pockets, and looked up at the taller man serenely. "Because my friend saw shards of glass on the ground near the girl's body. And, hypothetically of course, if you had been the one to push that poor woman off the platform, and you broke your glasses doing it, it would be a simple matter to match the brand of glasses you wear to the fragments that you left behind." He let that linger for a second. "All completely hypothetical, of course," he added pleasantly.

"I just dropped my glasses," protested the man. "Why should that be an instant link to me murdering someone?"

"It probably wouldn't be," agreed the Doctor. "Except, this compartment is nearly empty."

The man looked around. There were only eight people in total in the train compartment. "And?"

"And you're the only one standing up."

If the man had really pushed the girl onto the tracks, then he would've hopped onto the first train that he could find. He would've needed to hide any sort of evidence that he had, maybe even destroy it, which could only be accomplished at the next stop, where he could find some sort of rubbish bin.

"Can I have a look at your coat?" Ace asked, all innocence and smiles. He scowled, and pulled it away from her.

"Mind your own business, girlie."

Ace inwardly raged at him, but kept up the polite act. "But it would really help both of us if we could just look at your coat. If you really didn't do it-"

The Doctor snatched the beige coat from him before he could react. Ace looked at the strap that ran around the stomach to keep it in place. Or, rather, she looked at the conspicuous _absence _of a strap. "Hey, the piece that should be there was lying on top of the girl's body!" she said brightly, relishing every moment of this.

"What?" the man exclaimed, almost ferally.

The Doctor tucked the coat over his arm, and smiled benignly. "You see, if the girl had been holding onto your coat strap while she was pushed, you wouldn't be able to retrieve it, and would have to dispose of the evidence as quickly as possible so the police couldn't match the strap to your coat."

"Are we still talking hypothetically, Professor?" Ace asked, glancing up at the clock, which read '_Three minutes'_.

"You're police, aren't you?" the man said with something like sudden realisation. "Well, you can't arrest me. You _can't. _Because I wasn't here when she died. I only came into the station a minute before this train left. I couldn't have done it."

The man with the mobile phone looked up from his texting. "Liar."

The man Ace had now dubbed the murderer spun around to glare at him. "Whaddya mean-"

"He _means_," interrupted the Doctor, cutting off the brewing argument. "That you're quite obviously not telling the truth. Anyone here can see that."

Ace got it immediately. Two of the three woman were wearing dripping rain jackets. The other one had a transparent bubble umbrella lying next to her on the seat. One man had dripping wet hair, and the other's coat was soaked. She and the Doctor had used his brolly, but the remaining bloke wasn't in the least bit damp. The Doctor held up his coat. "Does this seem wet to you?"

He spluttered a bit.

"If you had got here a few minutes ago," Ace said triumphantly. "You'd know that it was raining outside. But if you'd got here _before _the rain started..."

"He'd have had to been here for at least half an hour," said the woman with the umbrella. The Doctor had that inexplicable look of pride and smugness that Ace often saw on his face when he finally worked something out. It was only now that she realised exactly how it must feel for him. She felt just as proud and smug as him because she had helped him work it out as well-

-and suddenly someone had just grabbed her around her wast and was holding a knife to her throat. She struggled as violently as she could- but soon stopped when the knife bit into her flesh and drew two perfect little droplets of blood.

Ow.

"Don't move, or I'll kill her," the murderer warned, and the vicious gleam in his eye left everyone with no doubt that he was telling the truth.

* * *

><p><strong>To be concluded...<strong>


	5. Curtain

**Chapter Five**

**Curtain**

* * *

><p>The Doctor frowned as if he had just been told that he couldn't eat the last biscuit at a tea party- which was a <em>really disproportionate response<em>, Ace thought. He could be at least a bit worried that someone was threatening to kill her. A bit of outrage would be nice. "I'm sure we can all work this out logically and calmly over a nice cup of tea," he offered.

"Give me my coat back," the man said coldly. The Doctor quickly tossed it back, and he caught it with the hand he wasn't using to brandish the knife. Ace caught the time on the digital display. _One minute. _And the train was slowing down.

_Oh, god. We're too late, _thought Ace. The train loudspeaker was saying something, but she couldn't quite hear it, being slightly distracted by the drama unfolding around her.

"You're an assassin, aren't you?" asked the Doctor, almost curiously. Ace wanted to shout at him to hurry up; the train was about to stop, but it was all she could do to breathe anyway. "A hired thug. Now, I wonder what that girl did to deserve a professional killer?"

"She saw too much," he sneered. "Just like you."

Out of the corner of her eye, Ace could see the man with the mobile phone slowly dialling a number. She thrashed around a bit more, not because she thought she could get free, but to distract him. The Doctor must have noticed, too, because she saw him wink ever-so-slightly at her. Or was that just a trick of the light?

"I'd appreciate it if you would put my friend down," he said. "I'm sure she would, too."

The train stopped, but the doors hadn't opened yet.

"What will you do to me if I don't?"

"Nothing," said the Doctor happily. "But I'm sure the gentleman behind you will."

The murderer spun around, loosening his grip on Ace, who promptly punched him in the jaw. There was no one behind him, and there never had been.

"Good work, Ace," the Doctor said as the doors hissed open. He pressed the alarm button on the side of the door. "Would you mind holding him down until the police arrive?"

"No problem," said Ace, and sat on him, twisting his arm up behind his back until he yelped. The passengers on the train compartment all looked at each other.

"Er," said one. "Can we go?"

"Sure," shrugged Ace. "Just send the police in here if you happen to see them, okay?"

They filed out, still sending nervous looks back at Ace and the Doctor. The man with the mobile phone hung back for a moment.

"Thank you very much," said the Doctor to him warmly.

"We really couldn't have done this without you," Ace added with a genuine smile.

He shook his head. "You really aren't police, are you?"

The Doctor and Ace looked at each other, and Ace burst out laughing. "Police? Can you imagine him in a uniform?"  
>The Doctor grimaced a bit, as if trying to picture it, deciding that it was too much effort, suddenly realising what it would actually look like, and then immediately trying to forget it. "Er, yes. Quite. No, we're just passers-by."<p>

The man with the phone left the train, leaving them alone with the man Ace was currently sitting on. She frowned with a sudden thought. "Professor," she said suspiciously. "You didn't plan this all as a test for me, did you?"

He looked genuinely shocked. "You think I'd plan the murder of an innocent girl just as a test?"

"Well, no," she admitted. "But you could have found out beforehand and, I don't know, got us here just to do this whole deduction business."

He shook his head; leaned over and tapped her nose fondly. "Whenever did you become so suspicious?"

"I had an excellent teacher," she replied. "Now, after we've taken care of this, can we get something to eat? I'm _starving._"

He smile, and leaned back in his seat. "I know an excellent place near where we are right now. They serve arguably the best sushi on this planet."

"Sounds good," Ace said. She paused. "I was wrong," she added. "You're the Sherlock Holmes here."

"I prefer to think of myself as Hercule Poirot," he said, with a little quirk of his mouth.

"And I suppose that makes me Miss Marple," she returned.

"Yes," said the Doctor. "I rather suppose it does."

* * *

><p><strong>The End.<strong>


End file.
